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..,'i d. Unreulated.Ccim Onent. 50Z.800at~es. This is Commercial Forest Land with a potential yiel of about 450 mi lion board feet of sawtimber that cannot be counted on for continuous timber production. It includes recreation and administrative areas where timber harvest is permissible, but not a goal of management, and some ecotones (see below). Timber will be cut on some of these lands. but it will be incidental to the planned . harvest for the Forest. . Aspen. not included in the Standard and Special components, is included in the Unregulated component until additional research work can be completed on the management of this species and the land it occupies in southwestern Colorado. Aspen represents about 246.000 acres of this component. . . Much of the understocked ponderosa pine stands are classified as unregulated because of the heavy oakb"ush understory (Quercus gambelii). If residual pine trees are removed, the oakbrush will completely occupy the site. Long-term silvicultural treatment for these areas is discussed later. . The Land Use Classification acreages are graphically illustrated in Figure 4. The fOllowing figure illustrates how the standard Multiple Use Management Zone Classifi- cation of the Multiple Use Plan guides the Land Use Classification used in the Timber Management Plan. See Parts 1 and 11 of DES. Appendix I. D. Timber Manaoement Under the Proposed Plan 1. Timber management will be applied to the following forest types: The ponderosa pine type is found at the lower elevations from 7000 to 8500 feet range in pure stands and in mixture with other species. Much of the ponderosa pine type is in an understocked condition at the present time. The Dou las-fi white fir type is found at the BOOO to 9500 feet elevational range. It var es great y in tree species composition and includes Douglas-fir, white fir. corkbar fir. Eng&lmann spruce, blue spruce. ponderosa pine. southwestern white pine and quaking aspen. All grow together in some stands; in others. only two or three species are fOund. Douglas-fir is the predominant species in this type. The Enoelmann spruce/alpine fir type occurs at elevations between 9000 and 11.500 feet on cooT. moist sites in the upper valleys and plateaus. It occurs on sites gener~lly rich in timber productivity. water yield and scenic beauty. The aspen type is found throughout a wide elevation band of the Forest on a wide variety of soils. It often forms the forested border with lower elevation shrub types. Aspen grows as islands in the spruce-fir type and occasionally as a sprawling shrub at timberline; It is a short-lived species which appears following timber fires. and normally will be replaced by conifers in the plant succession process. Some of the timber types are located in what is called ecotone zones. An ecotone can be described as the t~ansition or tension zone between two or more plant communities. The two most important ecotones on the San Juan National Forest are: (1) the ponderosa .pine-pinyon pine ecotone at the lower elevations. and (2) the Engelmann spruce-alpine tundra ecotone at the upper elevations. The lands in these ecotones are not highly productive for.tree growth. Following any disturbance of the standing timber in these areas. the predominant vegetation will usually be pinyon pine or alpine sedges. respectively. These two ecotones have been classed as unregulated timber land. meaning timber management activities may occur but not on a planned basis for these areas. 2. Rotation Aces A period of years required to establish and grow timber crops to a specified condition of maturity is called a rotation. On the San Juan National Forest. the aspen type will generally be managed on an 80-Year rotation age and the othe" forest types will be managed on a 120-year rotation age. 8